ABSTRACT
Aim To investigate the role and potential mechanism of methyltransferase-like 5 (METTL5) in triple-negative breast cancer (TNBC) . Methods The expression of METTL5 in TNBC tumor tissues and cell lines was detected by immunohistochemistry and Western blot. After shRNA targeting METTL5 (shRNAMETTL5) was transfected into TNBC cells, cell proliferation, migration and invasion were detected by CCK-8, colony formation, wound healing and Transwell assays, respectively. Western blot was used to detect the expression of Wnt/p-catenin signaling-related key proteins. A xenograft tumor model was constructed to verify the effect of METTL5 knockdown on the growth of TNBC cells and Wnt/p-catenin signaling activity in vivo. Results The expression of METTL5 was up-regulated in TNBC tumor tissues and cell lines (P < 0. 01) . Knockdown of METTL5 significantly inhibited the proliferation, migration and invasion of TNBC cells and reduced the expression of Wnt/p-catenin signaling molecules (3-catenin, cyclin Dl, matrix metalloproteinase (MMP) -2 and MMP-7 (all P < 0. 01) . Knockdown of METTL5 reduced tumor growth and Wnt/pcatenin signaling activity in vivo. Conclusions Knockdown of METTL5 can inhibit the proliferation, migration and invasion of TNBC cells, which may be related to the inhibition of Wnt/p-catenin signaling pathway.
ABSTRACT
Methyltransferase-like 3 (METTL3), as the most important methylase of N6-methyladenine (m6A),plays an important role in the development and progression of breast cancer by influencing various regulatory mechanisms, such as methylation level, mRNA stability of cancer-related genes, oncogene expression and cancer cell signaling pathways. This paper reviews the regulatory mechanism of METTL3 in breast cancer and summarizes the latest research progress of METTL3 in the development and progression of breast cancer.
ABSTRACT
AIM: To investigate the role and mechanism of methyltransferase-like 3(METTL3)-mediated N6-methyladenosine(m6A)methylation modification in regulating biological activity of vascular endothelial cells in the pathogenesis of choroidal neovascularization.METHODS: Human umbilical vein endothelial cells(HUVEC)cultured in vitro were divided into the following groups: control group(normal culture), low density lipoprotein(LDL)group, fluorescence-labelled LDL(Dil-LDL)group, 12.5μg/mL and 25μg/mL oxidized LDL(ox-LDL)groups, 12.5μg/mL and 25μg/mL fluorescence-labelled ox-LDL(Dil-ox-LDL)groups, DMSO group, STM2457(METTL3 inhibitor)group, DAPT group; and monkey retina-choroidal endothelial cells(RF/6A)cultured in vitro were divided into control group, DMSO group, 12.5 μg/mL ox-LDL group, and DAPT group. Endocytosed lipoprotein level was examined through fluorescence microscopy. RNA m6A methylation level was detected through a dot blot assay. Protein and RNA levels of METTL3 or angiogenesis-related markers were measured through Western blot assays and real-time quantitative polymerase chain reaction(RT-qPCR), respectively. METTL3 expression and localization were investigated through immunofluorescence. Cell migratory and tube formation capacities were assessed through transwell migration and tube formation assays, respectively.RESULTS: Endocytosed lipoprotein levels in HUVECs exposed to Dil-LDL, 12.5μg/mL and 25μg/mL Dil-ox-LDL groups were significantly higher than those in the control group. 12.5μg/mL and 25μg/mL ox-LDL groups significantly increased m6A methylation(all P<0.05), METTL3 protein expression(all P<0.01), and cell migration and angiogenesis capacities(all P<0.01). METTL3 mRNA level was significantly unregulated in the 12.5μg/mL ox-LDL group(P<0.05). In comparison to the DMSO group, the addition of STM2457 caused significant decrease in m6A methylation level(P<0.05), expression of VEGF and other angiogenesis-related markers(all P<0.05), cell migration and angiogenesis capacities(all P<0.01)and the expression of NICD(P<0.05). However, there were no significant differences in METTL3 protein and mRNA levels(all P>0.05). The expression of VEGF and NICD(all P<0.05), as well as the ability of cell migration and angiogenesis of RF/6A, was all significantly decreased in the DAPT group compared to the DMSO group(all P<0.01).CONCLUSION: METTL3-mediated m6A methylation modification promotes angiogenesis in vascular endothelial cells via the Notch signaling pathway in the pathogenesis of choroidal neovascularization.